When OSA was announced I really expected the US to state clearly that they wouldn't let UK to threaten US citizens with millions of fines if they practice their rights to Free Speech.

Because this is what's happening, the UK is making open threats against US citizens when they practice their rights to Free Speech. See e.g. Lobsters' take on it: they just wanted to have a webforum in the US but they couldn't because a foreign country threatened them with huge fines. No protection from the US.

"Just geoblock UK" seemed like a good enough in practice solution, although it is more action needed than I'd prefer.